In 3rd Generation Partnership Project (3GPP), the network structure and various technologies needed for a terminal's movement between a 3GPP wireless communication network and a Wireless Local Area Network (WLAN) network are called interworking WLAN. The multi-mode wireless communication technology has evolved to use multiple wireless communication technologies at the same time. The use of multiple wireless communication technologies simultaneously thereby increases transfer rates per unit time or improves the reliability of the terminal.
In wireless communication, spectrum is very rare resource. A licensed band represents a frequency band that is exclusively licensed to a specific operator to provide specific wireless services. On the other hand, an unlicensed band represents a frequency band that is not allocated to a specific operator, but is opened so that all entities meeting the predefined requirements may use the frequency band.
In some regions in the world, unlicensed band technologies need to abide to certain regulations, for example, Listen-Before-Talk (LBT), and channel bandwidth occupancy requirements. LBT results in an uncertainty of channel availability. For instance, an unlicensed band may be available at any time during a subframe.
WLAN that uses Wireless Fidelity (WiFi) is the typical wireless communication technology used in the unlicensed band. Time granularity of current Long Term Evolution (LTE) is much larger than that of WiFi, which leads to the low competitive strength of License Assisted Access (LAA) with LBT. As such, fair coexistence between LTE and other technologies such as WiFi as well as between LTE operators is expected. In order to be more competitive in the unlicensed band, fractional subframe transmission may be performed.
The fractional subframe transmission may use at least one fractional subframe. Since merely a portion of symbols of a factional subframe are available for data transmission, the end of the fractional subframe transmission may be uncertain. However, for both a transmitter and a receiver, the end of the fractional subframe transmission is an important factor for perform the fractional subframe transmission efficiently. Therefore, there is a need to estimate the end of the fractional subframe transmission.